Objective of the project:

The overall goal of this project is to develop high-performance integrated robotic systems for intra-operative multiple MRI-guided interventions, including 1) prostate brachytherapy, 2) bladder photothermal therapy, 3) functional and stereotactic neurosurgery, and 4) transoral laser microsurgery. This project will integrate advanced technologies from different areas of medical robotics, namely fast intra-op MRI, high-performance MR-safe/conditional actuators and real-time MR-tracking units, with the aim at becoming benchmark systems to engage multidisciplinary collaborations with surgery and radiology. Potential downstream application will be foreseen for further R&D with the currently strong and sustainable support from our industrial partners.

 

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Significance of the project:

Advanced surgical robotics has attracted significant research interest in supporting magnetic resonant imaging (MRI)-based visual guidance for effective navigation of surgical instruments. MRI offers excellent image contrast for soft tissue details and differentiations, allowing clinicians to identify tumors margins and critical neurovascular and muscular structures. By acquiring intra-operative (intra-op) MR images rapidly, 3-D critical regions showing the physiological changes of tissue can be visualized. In minimally invasive interventions, such in situ guidance providing access routes to the target anatomy, rendered based on imaging data, can enable a distinct awareness of the configuration of robotic instrument relative to the anatomy of surgical interest.

 

Integration of multidisciplinary technologies for intra-op MRI-guided interventions

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In this project, fast image processing techniques, novel MR-safe/conditional robotic components, as well as real-time MR-tracking are proposed to fulfil the unmet technological requirements for providing safe, precise and effective control of instruments in MRI-guided minimally invasive surgeries. Advanced computing technique is presented to enable instant, frequent update of anatomical roadmap using reliable image registration based on intra-op imaging data, since its slow computational process is still the major bottleneck in real implementation on many image-guided interventions. The proposed MR-safe/conditional robotic components could be even operated in MRI environment that imposes significant difficulties on conventional robot operations due to the tremendously strong magnetic field generated by the scanner. Soft continuum robotic manipulator made of biocompatible elastomer is also presented to facilitate luminal exploration while still guaranteeing the diagnostic and therapeutic capabilities. This soft robot would act as the next-generation of endoscope in the new standards of less pain, low cost, single use and zero chance of cross-infection. In addition, the proposed miniaturized tracking units can be integrated with minimal invasive surgical devices (e.g. catheter), providing accurate real-time positional tracking. Not only can they be visualized in the MR images intra-operatively, they can also close the control loop of the robotic interventions.

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Integrated robotic platform for various MRI-guided minimal invasive interventions

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The proposed MR-conditional robotic platform will be the first of its kind which integrates advanced multidisciplinary technologies of accelerated intra-op MR image registration, enhanced control of flexible instrument (e.g. cystoscope), real-time MR-tracking units and high-performance MR-safe actuation. Successful completion of the proposed work will facilitate comprehensive pre-clinical validation in human trials. A new line of study will be developed, attracting clinicians to push the envelope of robot-assisted interventions, in particular for the procedures stated in the following section.

 

Main projects incurred:

 

Intra-op MRI-guided prostate brachytherapy: Prostate cancer is a common cancer. Let alone in the US, above 450,000 new cases are expected to be diagnosed, more than double by the year 2015. The use of intra-op MR images (e.g. T2-weighted or diffusion tensor) in guiding the biopsy or drug delivery to prostate gland becomes the trend led by minimally invasive approaches. It will eliminate the need for any image fusion with transrectal ultrasound (TRUS), which is commonly used as the intra-op imaging, causing much spatial error in surgical planning. Our proposed MR-conditional robotic platform could i) resolve the surgical complications of radical prostatectomy with the presence of deep venous thrombosis, pulmonary embolism, urinary incontinence, and impotence; ii) reduce the failure rate of biopsy or needle insertion, since every needle placed can be imaged and assessed in 3D, and then repositioned before further insertion; iii) improve the accuracy of brachytherapy seeds placement/distribution (<1mm RMS).

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Intra-op MRI-guided bladder photothermal therapy:  Non-muscle-invasive bladder cancer (NMIBC) accounts for 80% of all diagnosed cases of bladder cancer, and has a recurrence rate of up to 61% at one year, and 78% at five years, despite bladder cancer ranked 8th by the mortality rate worldwide. In cases where the cancer progresses to muscle-invasive bladder cancer, complete removal of the bladder, called radical cystectomy, is usually performed. The requirement of urine diversion following this procedure is associated with the worst health-related quality of life for patients. This fact creates great demand for a more complete and reliable first-line treatment to NMIBC. The successful integration of MRI-guided, robot-assisted cystoscopic techniques with gold-nanoparticle-based photothermal therapy (PTT) would present a timely improvement over current first-line treatments for bladder cancer, addressing several key points: i) improved tumor localization by the use of MR-contrasting agents coated on tumor-accumulated GNPs, instead of relying on visual detection via cystoscopy; ii) reducing the recurrence rate of NMIBC by providing complete tumor ablation, thereby lowering the dependence on frequent post-operative surveillance; iii) minimizing the possibility of patient progression to the advanced stages of bladder cancer, which require curative procedures that significantly diminish patient quality-of-life.

 

Intra-op MRI-guided functional and stereotactic neurosurgery: Deep brain stimulation (DBS) is one of the common neurosurgical procedures for alleviate symptoms associated with essential tremor, Parkinson’s disease (PD) and dystonia, in which a coiled wire is placed at different regions of the brain, such as ventrointermediate nucleus (VIM) or subthalamic nucleus (STN), under stereotactic guidance to interfere with neural activity at the region. Under the MRI image, the STN and other critical brain structures can be clearly revealed. It is anticipated that our MR-conditional robotic system could: i) enhance the accuracy (±1mm) of electrode placement by coping with brain shifts using updated brain images and MR-tracked instruments; ii) decrease the risks of damaging the critical brain structure; iii) avoid the complications of local anaesthesia, thus adding confidence by having the post-procedural evaluations of surgical outcome based on images, instead of verbal/physical interaction with the awake patient during the procedure; iv) save the operation time from the repeated microelectrode recording (MER) as well as the image alignment with head frame. The procedural time will be reduced from approximately >330 to 180 minutes. The overall healthcare expenditure could be significantly reduced, also compensating the cost of using MRI.